Now, Car and Driver reports that Germany’s Federal Administrative Court in Leipzig has ruled that German cities have the authority to ban some high-polluting diesel vehicles, making Fiat Chrysler’s reported decision to cease diesel car production appear quite timely. Many cities in the country already have defined Umwelt (environmental) zones where cars incapable of passing Euro 4 emissions testing are forbidden, C/D says, but the court’s ruling today could see cities banning cars that fail to meet Euro 4, 5, and even 6 testing standards.

The case was brought by Deutsche Umwelthilfe (DUH) – a non-profit German environmental group that sued local authorities in Stuttgart and Düsseldorf after the air in both cities was found to have nitrogen oxides and carbon particulates in concentrations higher than is allowed by the EU.

According to Kraftfahrt-Bundesamt (Germany’s Federal Motor Vehicle Office), nearly 33 percent of the country’s 45.8 million registered vehicles run on diesel, meaning the impact of this case could be quite large. That’s especially the case if DUH successfully effects restrictions on Euro 5 diesel vehicles, which the group says could happen as soon as 2019, or if the federal courts in other European countries make similar rulings, allowing additional cities to enact bans that could make diesel vehicles untenable for many.

Fiat Chrysler Automobiles will reportedly phase out all its diesel-powered passenger cars by 2022, although truck and crossover models in the US aren’t expected to be affected.